Over the many decades that Marvel have been publishing comics, the company has accumulated quite the roster of characters, and with it, a similarly large portfolio of teams.
As such, there are likely numerous superhero groups from the House of Ideas that fans won't have heard of, especially if they aren't an avid reader of the comics.
However, for every well-known team that gets plenty of time in the spotlight, there's at least one that possesses some excellent potential in different media. The characters they feature are usually either ones that fans have already fallen in love with, or are heroes that would be as beloved as Captain America or Iron Man, if they only had the chance to be in the spotlight every once in a while.
The Avengers might be Earth's Mightiest Heroes, but they won't be around forever. The current incarnation featured in the MCU are due for a major reshuffle in the franchise's hotly anticipated fourth phase, and though members can always be replaced, there's more than one way to fill the hole left behind by the inevitable departures of Tony Stark and Steve Rogers...